I had noticed my site was a bit sluggish but only recently started investigating. I noticed this on my main site currently running WP 3.3.1. I did some testing on it and then tried my test install to see if it has the same issues. It does.
Using the webkit timeline, I see that s2member-o.php takes up a lot of time. (Nearly 1 second.)
I also use the P3 Plugin Profiler to test, and on the test site with all other plugins disabled, S2 member accounts for 98% of the site's load time. The webkit timeline shows about the same. This is with all other plugins disabled.
I have WP Super Cache installed on the main site, but it doesn't seem to help.
Any suggestions for speeding up S2 member?
Thanks